As liquid organic and polymer electrolytes continue to pose a major safety concern and shortened lifetime for current lithium ion batteries, solid lithium ion conducting electrolytes are sought for replacing liquid organic and polymer electrolytes. However, there are many difficulties being encountered in efforts to make solid electrolytes that possess the set of optimal characteristics needed to at least maintain such properties as the power output, charge/discharge efficiencies, capacity rating, and lifetime of current liquid and polymer electrolyte lithium batteries. In particular, it is highly desired for the solid electrolyte to exhibit high lithium ion conductivity, along with a negligible electronic conductivity, high electrochemical stability, and long-term stability against reactions with electrode materials.
Although some materials with such properties have been produced, their integration into lithium ion batteries as electrolytes has been significantly limited by the solid-state methods of synthesis currently used in preparing these materials. The solid state methods of synthesis possess numerous drawbacks, including the inability to adjust or optimize the particle size of the solid materials, or to render the solid material as a film, and particularly, thin films (e.g., up to or less than 1 micron) of uniform thickness. Another significant drawback of current solid-state methods of synthesis is their prohibitive cost and resistance to production scale up. A further significant drawback of current solid-state methods is their inability to be integrated into existing lithium ion battery assembly line manufacturing processes.